A non-reciprocal spintronic device and its fabrication method

Abstract

This invention discloses a non-reciprocal spintronic device, comprising a substrate and a non-reciprocal transport layer disposed on the substrate, a current input terminal, and a voltage test terminal, wherein both the current input terminal and the voltage test terminal are electrically connected to the non-reciprocal transport layer. Compared with the prior art, this invention has the following advantages: when an alternating current is applied to the current terminal of the device, a lock-in amplifier is used to detect the secondary signal at the voltage terminal in order to obtain spin-charge interconversion information; when the applied magnetic field is zero, a pure spin current is generated in the current direction, and no charge current is generated; under the application of an in-plane magnetic field, some electrons undergo directional movement, and the spin current is partially converted into a charge current; by controlling the relative direction of the external magnetic field and the current, this spin-charge interconversion information can be reflected in the second-order voltage term.

Description

Technical Field

[0001] This invention belongs to the field of spintronics technology, specifically relating to a non-reciprocal spintronic device and its fabrication method. Background Technology

[0002] Non-reciprocity describes the property that an object's motion in one direction differs from its motion in the opposite direction, and it is an important research topic in semiconductor physics, optics, and electronic circuits. The most widely used non-reciprocity effect is the diode effect, whose fundamental property is unidirectional conductivity. However, because diodes only utilize the charge degree of freedom of electrons, their applications are limited to traditional electronic devices.

[0003] Compared to the electron charge property utilized in traditional electronic devices, spintronic devices, which utilize the electron spin property, are expected to become the next generation of electronic devices due to their low energy consumption and high processing speed, playing an important role in information storage, transmission, and processing. Specifically, traditional PN junction-based diodes use N-type and P-type semiconductors to form space charge regions, and under the influence of an external electric field, charge control is achieved through the injection and extraction of non-equilibrium minority carriers. However, for devices that achieve specific functions through spin current, charge-based electronic devices and control methods are clearly no longer suitable. Therefore, the directional manipulation of spin current to achieve different spin accumulation states has become a new requirement in the field of spintronics.

[0004] To address the aforementioned requirements, certain topological materials have attracted widespread attention from researchers due to their unique topological electronic states. Taking topological insulators as an example, their bulk band gap contains gapless surface states, meaning that electrons in a certain momentum direction are locked with spins in a specific direction perpendicular to it. When current flows through a topological insulator, the distribution of electrons in k-space shifts, and this imbalance leads to an imbalance in spin distribution, resulting in a net spin accumulation on the surface of the topological insulator. With the assistance of an external magnetic field, the spin current can be partially converted into a charge current, thereby achieving different spin accumulation states and ultimately realizing the purpose of spin manipulation.

[0005] Besides topological insulators, topological half-metals, as a further extension of the concept of topological insulators, also possess topological surface states. Compared to topological insulators, which have metallic surfaces and insulating bulk states, exhibiting lower conductivity, topological half-metals have point or line contacts between their conduction and valence bands, resulting in better conductivity and greater practical application, making them ideal materials for spin control. Therefore, the fabrication of non-reciprocal spintronic devices based on topological half-metals has significant scientific and applied implications. Summary of the Invention

[0006] The purpose of this invention is to provide a non-reciprocal spintronic device that uses a magnetic field to control the spin flow portion to be converted into a charge flow, thereby changing the spin accumulation state of the device.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is: a non-reciprocal spintronic device, comprising a substrate and a non-reciprocal transport layer, a current input terminal and a voltage test terminal disposed on the substrate, wherein the current input terminal and the voltage test terminal are both electrically connected to the non-reciprocal transport layer.

[0008] Preferably, the substrate is made of silicon oxide, and the non-reciprocal transport layer is made of TaIrTe4. This invention uses a silicon oxide wafer as the substrate and a Dirac half-metal TaIrTe4 as the non-reciprocal transport layer, and grows electrodes using photolithography to construct a two-terminal device.

[0009] Preferably, when an alternating current is applied to a non-reciprocal spintronic device and a rotating in-plane magnetic field is applied, the angle between the second-order term of the resistance in the direction of the current flow and the magnetic field and the current exhibits a sinusoidal relationship; when an alternating current is applied to a non-reciprocal spintronic device and a rotating in-plane magnetic field is applied, the amplitude of the second-order term of the resistance in the direction of the current flow is linearly related to both the current intensity and the magnetic induction intensity.

[0010] Another object of the present invention is to provide a method for fabricating a non-reciprocal spintronic device, the method specifically comprising the following steps:

[0011] S1. Clean the substrate and perform oxygen plasma surface treatment on the cleaned substrate.

[0012] S2. Thinning TaIrTe4 and transferring the thinned TaIrTe4 to the substrate surface obtained in step S1 to obtain a non-reciprocal transport layer.

[0013] S3. Based on the electrode design, perform photolithography on the substrate surface obtained in step S2 to obtain the required electrode pattern.

[0014] S4. Electrons are grown on the surface of a substrate with an electrode pattern using electron beam evaporation.

[0015] S5. Remove the photoresist from the substrate surface in step S4 to obtain a non-reciprocal spintronic device.

[0016] Preferably, in step S1, the power range of the oxygen plasma surface treatment is 100-200W, and the treatment time is 3-10min.

[0017] Preferably, in step S2, the thickness of the thinned TaIrTe4 is 30-150 nm.

[0018] As a preferred option, the material used for the thinning process is heat-release tape.

[0019] Preferably, in step S3, the photolithography technique is selected from ultraviolet exposure or electron beam exposure.

[0020] Preferably, in step S4, the electrode is a double-layer electrode, the upper layer material of the double-layer electrode is Au or Cu, and the lower layer material of the double-layer electrode is Ti or Ta.

[0021] Preferably, in step S5, the material used to remove the photoresist is N-methylpyrrolidone.

[0022] Compared with existing technologies, this invention has the following advantages: When alternating current is applied to the current terminal of the device, a lock-in amplifier is used to detect the secondary signal at the voltage terminal in order to obtain information on spin-charge interconversion. When the applied magnetic field is zero, a pure spin current is generated in the current direction, and no charge current is generated; under the application of an in-plane magnetic field, some electrons undergo directional movement, and the spin current is partially converted into a charge current. By controlling the relative direction of the external magnetic field and the current, this spin-charge interconversion information can be reflected in the second-order voltage term; furthermore, the specific control method can be described by the nonlinear relationship between the second-order voltage term and the current intensity and magnetic induction intensity. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the non-reciprocal spintronic device of the present invention;

[0024] Figure 2 This is the curve showing the relationship between the second-order resistance term and the current-magnetic field angle of the non-reciprocal spintronic device of this invention.

[0025] Figure 3 This is a curve showing the relationship between the magnitude of the second-order resistance term and the magnetic flux density of the non-reciprocal spintronic device of this invention.

[0026] Figure 4 This is a curve showing the relationship between the magnitude of the second-order resistance term and the current intensity of the non-reciprocal spintronic device of this invention.

[0027] In the figure: 1-substrate; 2-non-reciprocal transport layer; 3-first current input terminal; 4-second current input terminal; 5-first voltage input terminal; 6-second voltage input terminal; 7-third voltage input terminal; 8-fourth voltage input terminal. Detailed Implementation

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This application specification and embodiments are merely exemplary.

[0031] This embodiment provides a non-reciprocal spintronic device, including a substrate 1 and a non-reciprocal transport layer 2, a current input terminal, and a voltage test terminal disposed on the substrate 1, wherein the current input terminal and the voltage test terminal are both electrically connected to the non-reciprocal transport layer 2.

[0032] In this embodiment, the substrate 1 is made of silicon oxide, and the non-reciprocal transport layer 2 is made of TaIrTe4. This invention uses a silicon oxide wafer as the substrate 1, and uses the Dirac half-metal TaIrTe4 as the non-reciprocal transport layer to grow electrodes via photolithography, thus constructing a two-terminal device.

[0033] The non-reciprocal spintronic device of this invention has the following characteristics: when an alternating current is applied to the non-reciprocal spintronic device and a rotating in-plane magnetic field is applied, the angle between the second-order term of the resistance in the direction of current flow and the magnetic field and current exhibits a sinusoidal function relationship; when an alternating current is applied to the non-reciprocal spintronic device and a rotating in-plane magnetic field is applied, the amplitude of the second-order term of the resistance in the direction of current flow is linearly related to both the current intensity and the magnetic induction intensity.

[0034] This embodiment also provides a method for fabricating a non-reciprocal spintronic device, which specifically includes the following steps:

[0035] S1. Clean the silicon oxide wafer and perform oxygen plasma surface treatment on the cleaned silicon oxide wafer. The power range of the oxygen plasma surface treatment is 100-200W, and the treatment time is 3-10min.

[0036] S2. The TaIrTe4 is thinned using heat-release tape, and the thinned TaIrTe4 is transferred to the substrate surface obtained in step S1 using heat-release tape again to obtain a non-reciprocal transport layer. The thickness of the thinned TaIrTe4 is 30-150 nm.

[0037] S3. According to the electrode design, the silicon oxide surface obtained in step S2 is photolithographically lithographically processed using ultraviolet exposure or electron beam exposure technology to obtain the required electrode pattern. The electrode is a double-layer electrode, with the upper layer material of the double-layer electrode being Au or Cu and the lower layer material of the double-layer electrode being Ti or Ta.

[0038] S4. Electrodes are grown on the silicon oxide surface with electrode patterns using electron beam evaporation.

[0039] S5. Use N-methylpyrrolidone to remove the photoresist on the silicon oxide surface from step S4 to obtain a non-reciprocal spintronic device.

[0040] The technical effects of the present invention will be described below with reference to specific embodiments.

[0041] Example 1

[0042] like Figure 1 As shown, a non-reciprocal spintronic device includes a silicon oxide substrate 1 and a non-reciprocal transport layer 2 disposed on the substrate 1, a current input terminal, and a voltage test terminal. The current input terminal and the voltage test terminal are both electrically connected to the non-reciprocal transport layer 2. The material of the non-reciprocal transport layer 2 is TaIrTe4 single crystal. In this embodiment, the current input terminal includes a first current input terminal 3, a second current input terminal 4, a first voltage input terminal 5, a second voltage input terminal 6, a third voltage input terminal 7, and a fourth voltage input terminal 8.

[0043] The fabrication method of the non-reciprocal spintronic device in this embodiment is as follows:

[0044] S1. Place the silicon oxide substrate 1 (SiO2 thickness of 500nm) into acetone, deionized water and ethanol in sequence for ultrasonic cleaning, each for 10-15 minutes, and finally blow dry.

[0045] S2. Perform oxygen plasma surface treatment on the cleaned silicon oxide substrate 1 with a power of 150w and a treatment time of 5min.

[0046] S3. Transfer the TaIrTe4 single crystal onto a heat-release tape and perform multiple thinning operations to obtain a nanometer-thick TaIrTe4. After heat release, transfer the thinned TaIrTe4 crystal onto a silicon oxide substrate 1 to obtain a TaIrTe4 single crystal 2.

[0047] S4. Photoresist is spin-coated onto a silicon oxide substrate with TaIrTe4 single crystal 2, and pre-baking, exposure, and development are performed to obtain the desired electrode pattern. This photolithography process uses ultraviolet exposure technology.

[0048] S5. Using electron beam evaporation, 10nm Ti and 120nm Au are grown on a silicon oxide substrate with electrode patterns, wherein Ti is an adhesion layer between the substrate and Au.

[0049] S6. After the electrode growth is completed, the silicon oxide substrate is placed in N-methylpyrrolidone to remove the photoresist and obtain a non-reciprocal spintronic device, thus obtaining a patterned electrode.

[0050] The non-reciprocal spintronic device prepared in Example 1 was subjected to electrical testing by passing an alternating current through it. An in-plane rotating magnetic field was applied, and the secondary resistance signal at the current input terminal was monitored using a lock-in amplifier. Figure 2 As shown, the second-order resistance term of this device has a sinusoidal relationship with the angle between the magnetic field and the current; as... Figure 3 and Figure 4 As shown, this device can change the spin distribution state by applying an external magnetic field, successfully achieving directional control of the spin.

[0051] While the disclosure is as stated above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the protection scope of this invention.

Claims

1. A non-reciprocal spintronic device, characterized in that, The device includes a substrate (1) and a non-reciprocal transport layer (2) disposed on the substrate (1), a current input terminal, and a voltage test terminal, wherein the current input terminal and the voltage test terminal are electrically connected to the non-reciprocal transport layer (2); the substrate (1) is made of silicon oxide, and the non-reciprocal transport layer (2) is made of TaIrTe. 4； When an alternating current is applied to a non-reciprocal spintronic device and a rotating in-plane magnetic field is applied, the second-order term of the resistance in the direction of the current flow has a sinusoidal relationship with the angle between the magnetic field and the current. When an alternating current is applied to a non-reciprocal spintronic device and a rotating in-plane magnetic field is applied, the amplitude of the second-order term of the resistance in the direction of the current flow is linearly related to both the current intensity and the magnetic induction intensity.

2. A method for fabricating a non-reciprocal spintronic device as described in claim 1, characterized in that, The preparation method specifically includes the following steps: S1. Clean the substrate (1) and perform oxygen plasma surface treatment on the cleaned substrate (1); S2. Thinning TaIrTe4 and transferring the thinned TaIrTe4 to the surface of the substrate (1) obtained in step S1 to obtain a non-reciprocal transport layer (2). S3. Based on the electrode design, perform photolithography on the surface of the substrate (1) obtained in step S2 to obtain the required electrode pattern; S4. Electrodes are grown on the surface of a substrate (1) with an electrode pattern using electron beam evaporation. S5. Remove the photoresist on the surface of the substrate (1) in step S4 to obtain a non-reciprocal spintronic device.

3. The method for fabricating a non-reciprocal spintronic device as described in claim 2, characterized in that, In step S1, the power range of the oxygen plasma surface treatment is 100-200W, and the treatment time is 3-10min.

4. The method for fabricating a non-reciprocal spintronic device as described in claim 2, characterized in that, In step S2, the thickness of TaIrTe4 after thinning is 30-150 nm.

5. The method for fabricating a non-reciprocal spintronic device as described in claim 4, characterized in that, The material used for the thinning process is heat-release adhesive tape.

6. The method for fabricating a non-reciprocal spintronic device as described in claim 2, characterized in that, In step S3, the photolithography technique is selected from ultraviolet exposure or electron beam exposure.

7. The method for fabricating a non-reciprocal spintronic device as described in claim 2, characterized in that, In step S4, the electrode is a double-layer electrode, the upper layer material of the double-layer electrode is Au or Cu, and the lower layer material of the double-layer electrode is Ti or Ta.

8. The method for fabricating a non-reciprocal spintronic device as described in claim 2, characterized in that, In step S5, the material used to remove the photoresist is N-methylpyrrolidone.

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